How to Mold Fiberglass Props
THE ADVANTAGES of fiberglass props-strength, rigidity, safety, and superior performance-have made them a popular item in competitive modeling events. Fiberglass props are useful whenever resistance to de-pitching is desired, or whenever high rpm are encountered. A fiberglass prop will resist flying into pieces at a high rpm. This makes it an ideal choice for free flight, CL, and RC racing events. Its rigidity lends itself to events, such as Carrier, that require the engine to run at more than one rpm, because the prop does not "throb" at a low rpm like a nylon prop occasionally does.
How to Mold Fiberglass Props
THE MATERIALS required for making a prop are fiberglass rovings, resin, disposable gloves, sharpened sticks, dye, and wax paper. The rovings should be coarse enough so that a 36" length weighs about 2 grams. You may find that the most economical way to purchase the glass is in a cloth form called woven roving. The material in this cloth has a very coarse weave and can easily be pulled apart one strand at a time. The resin should be selected for its rigidity and its ability to wet the rovings. It is a good idea to talk with the man at the fiberglass or plastics supply house-his help might be invaluable. Epoxy resins are very rigid, but they must be chosen with care as they do not generally wet the rovings well. Also, some epoxy resins are very toxic. The polyester resins generally wet the rovings well but are not as rigid as the epoxies. The epoxies will also withstand hot runs better; when the engine shaft gets very hot, polyesters will sometimes slip on the drive washer.
